Online service providers facilitate access to information and services by providing interactive user interfaces (UIs) that help users navigate to desired resources. For example, in the case of a system for communicating using chat messages, a UI allows a chat participant to invoke actions, such as establishing a communications link, through the selection of screen objects such as icons, windows, and drop-down menus. A chat participant may select a chat room to exchange chat messages with other chat participants. A chat room may be associated with subject matter.